U.S. patent application number 10/264835 was filed with the patent office on 2004-04-08 for method for automated design of orthotic and prosthetic devices.
Invention is credited to Fourroux, Marvin, Watson, Keith.
Application Number | 20040068337 10/264835 |
Document ID | / |
Family ID | 32042339 |
Filed Date | 2004-04-08 |
United States Patent
Application |
20040068337 |
Kind Code |
A1 |
Watson, Keith ; et
al. |
April 8, 2004 |
Method for automated design of orthotic and prosthetic devices
Abstract
A method for automated design of orthotic and prosthetic devices
has been developed. The method includes scanning a three
dimensional model of the patient's limb with a laser scanner. The
model is loaded into a computer for use in manufacturing an
orthotic or prosthetic device. Before the model is used, it is
modified by reducing the overall volume of the model by up to
twelve percent of the total volume. Also the model's distal end
length is reduced by a calculated percentage of the thickness of a
prosthetic liner to be worn with the prosthetic device.
Inventors: |
Watson, Keith; (Huntsville,
AL) ; Fourroux, Marvin; (Huntsville, AL) |
Correspondence
Address: |
BRADLEY ARANT ROSE & WHITE LLP
200 CLINTON AVE. WEST
SUITE 900
HUNTSVILLE
AL
35801
US
|
Family ID: |
32042339 |
Appl. No.: |
10/264835 |
Filed: |
October 4, 2002 |
Current U.S.
Class: |
700/98 |
Current CPC
Class: |
A61F 2/80 20130101; A61F
5/01 20130101; A61F 2/5046 20130101; A61F 2002/5047 20130101 |
Class at
Publication: |
700/098 |
International
Class: |
G06F 019/00 |
Claims
What is claimed is:
1. A method for creating a representation of a limb suitable for
constructing a prosthetic device, comprising: scanning a three
dimensional representation of the limb into a computer system;
reducing the volume of the three dimensional representation of the
limb by up to twelve percent of the total volume of the limb; and
reducing the distal length of the three dimensional representation
of the limb by a calculated percentage of the distal thickness of a
prosthetic liner to be worn with the prosthetic device.
2. The method of claim 1, further comprising: identifying boney
prominences of the limb that are suitable for an overlay.
3. The method of claim 1, where the limb is an amputated leg.
4. The method of claim 3, where the leg is amputated below the
knee.
5. The method of claim 1, where limb is scanned by a laser
scanner.
6. The method of claim 1, where volume of the representation is
reduced between three and five percent of the total volume of the
limb.
7. The method of claim 1, where the distal length of the
representation is reduced by between 2 millimeters and 8
millimeters.
8. A method for creating a representation of a limb suitable for
constructing a prosthetic device, comprising: step for creating a
representation of the limb with a computer system; step for
reducing the volume of the representation of the limb; and step for
reducing the distal length of the representation of the limb.
9. The method of claim 8, further comprising: step for identifying
areas of the limb suitable for an overlay.
10. A method for creating a representation of a limb suitable for
constructing an orthotic device, comprising: scanning a three
dimensional representation of the limb into a computer system; and
identifying boney prominences of the limb that are suitable for an
overlay.
11. The method of claim 10, where the limb is a foot.
12. The method of claim 10, where the limb is scanned by a laser
scanner.
13. A method for creating a representation of a limb suitable for
constructing an orthotic device, comprising: step for creating a
representation of the limb with a computer system; and step for
identifying areas of the limb that are suitable for an overlay.
14. A method for creating a representation of a limb suitable for
constructing a prosthetic liner, comprising: scanning a three
dimensional representation of the limb into a computer system; and
transmitting the three dimensional representation of the limb to a
manufacturing facility for the prosthetic liner.
15. The method of claim 14, where the limb is an amputated leg.
16. The method of claim 15, where the leg is amputated below the
knee.
17. The method of claim 14, where the limb is scanned by a laser
scanner.
18. A method for creating a representation of a limb suitable for
constructing a prosthetic liner, comprising: step for creating a
representation of the limb with a computer system; and step for
using the representation of the limb to manufacture a customized
prosthetic liner.
Description
BACKGROUND OF INVENTION
[0001] 1. Field of the Invention
[0002] The invention relates generally to a method for computer
aided design. More specifically, the invention relates to automated
design for orthotic and prosthetic devices.
[0003] 2. Background Art
[0004] The design and manufacture of prosthetic and orthotic
devices requires custom fitting for a proper and comfortable fit
for a patient. FIG. 1 shows a prior art example of an attached
prosthetic limb 10. A patient's limb 12 is first fitted with a
liner 14. The limb 12 and liner 14 then fit into the socket 16 of
the prosthetic limb 18. FIG. 1b shows the patient's limb 12 with
the liner 14 before the limb is inserted in the socket. FIG. 1c
shows a liner 14 with an optional distal attachment mechanism 20.
The mechanism 20 is used to physically attach the liner to the
interior of the socket.
[0005] The liner is typically made of a malleable gel material,
such as urethane or silicone that is sometimes covered on the
exterior with a cloth layer called a "wick". The purpose of the
liner is to provide cushioning and comfort to the patient. The
liner provides a pseudo-hydraulic action that absorbs the energy
exerted by gravity and the weight of the patient. The vast majority
of the mass of a typical liner is gel while the wick only serves as
an exterior cover. A liner is usually tapered in shape with the
thickest portion being the distal end. It typically has a
decreasing thickness towards the proximal end. The thickness of the
liner usually ranges from 2-16 mm. The proximal end thickness
typically varies from 2-6 mm, while the distal end thickness varies
from 5-16 mm. However, the thickness may vary outside these ranges
based on the needs of the individual patient.
[0006] FIGS. 2a and 2b show a prior art example of a custom molded
orthosis 22. The patient's limb fits into a frame 26 that is
customized for the individual patient. The limb is held in place by
multiple straps 28. The limb may also be covered with a liner or
similar device to ensure a comfortable fit and provide protection
for the limb. An orthosis of the type shown is typically used to
support and stabilize the compromised limb.
[0007] Prior art methods of customizing prosthetic and orthotic
devices for individual patients involved taking an anatomical
impression of the patient's limb. The impression is made by taking
a casting of the patients' limb by wrapping the limb with plaster
wrappings. After drying, the casting is removed from the limb and a
model of the limb is made by using the casting as a mold. The model
of the limb is the used to fashion a customized prosthetic or
orthotic device for the patient.
[0008] Even with a skilled practitioner, the casting of the limb is
messy, time-consuming, and it is prone to errors. Typically, the
casting practitioner must manipulate the limb's soft tissue and
bony prominences to achieve a proper anatomical alignment. This
technique often requires multiple re-castings due to
inconsistencies in the alignment.
SUMMARY OF INVENTION
[0009] In some aspects, the invention relates to a method for
creating a representation of a limb suitable for constructing a
prosthetic device, comprising:
[0010] scanning a three dimensional representation of the limb into
a computer system;
[0011] reducing the volume of the three dimensional representation
of the limb by up to twelve percent of the total volume of the
limb; and reducing the distal length of the three dimensional
representation of the limb by a calculated percentage of the distal
thickness of a prosthetic liner to be worn with the prosthetic
device.
[0012] In other aspects, the invention relates to a method for
creating a representation of a limb suitable for constructing a
prosthetic device, comprising:
[0013] step for creating a representation of the limb with a
computer system; step for reducing the volume of the representation
of the limb; and step for reducing the distal length of the
representation of the limb.
[0014] In other aspects, the invention relates to a method for
creating a representation of a limb suitable for constructing an
orthotic device, comprising:
[0015] scanning a three dimensional representation of the limb into
a computer system;
[0016] and identifying boney prominences of the limb that are
suitable for an overlay.
[0017] In other aspects, the invention relates to a method for
creating a representation of a limb suitable for constructing an
orthotic device, comprising:
[0018] step for creating a representation of the limb with a
computer system; and step for identifying areas of the limb that
are suitable for an overlay.
[0019] In other aspects, the invention relates to a method for
creating a representation of a limb suitable for constructing a
prosthetic liner, comprising:
[0020] scanning a three dimensional representation of the limb into
a computer system;
[0021] and transmitting the three dimensional representation of the
limb to a manufacturing facility for the prosthetic liner.
[0022] In other aspects, the invention relates to a method for
creating a representation of a limb suitable for constructing a
prosthetic liner, comprising:
[0023] step for creating a representation of the limb with a
computer system; and step for using the representation of the limb
to manufacture a customized prosthetic liner.
[0024] Other aspects and advantages of the invention will be
apparent from the following description and the appended
claims.
BRIEF DESCRIPTION OF DRAWINGS
[0025] It should be noted that identical features in different
drawings are shown with the same reference numeral.
[0026] FIG. 1a shows a prior art example of an attached prosthetic
limb.
[0027] FIG. 1b shows a prior art example of a limb with a
liner.
[0028] FIG. 1c shows a prior art example of a limb with a liner and
a distal end connector.
[0029] FIGS. 2a and 2b show prior art examples of a fitted
orthosis.
[0030] FIG. 3 shows a schematic of one embodiment of the present
invention with the equipment for automated design of a prosthetic
device.
[0031] FIGS. 4a, 4b, and 4c show computer generated views of the
patient's limb in accordance with one embodiment of the present
invention.
[0032] FIGS. 5a, 5b, and 5c show computer generated views of the
patient's limb with the volumetric adjustments in accordance with
one embodiment of the present invention.
[0033] FIGS. 6a, 6b, and 6c show computer generated views of the
patient's limb with the distal length adjustments in accordance
with one embodiment of the present invention.
[0034] FIGS. 7a, 7b, and 7c show computer generated views of the
patient's limb with the bony prominences identified in accordance
with one embodiment of the present invention.
[0035] FIGS. 8a, 8b, and 8c show computer generated views of the
patient's limb with the areas of overlay adjustments identified in
accordance with one embodiment of the present invention.
[0036] FIG. 9 shows a schematic of one embodiment of the present
invention with the equipment for automated design of an orthotic
device.
[0037] FIG. 10a, 10b, and 10c show computer generated views of the
patient's limb with the bony prominences identified in accordance
with one embodiment of the present invention.
[0038] FIGS. 11a, 11b, and 11c show computer generated views of the
patient's limb with the areas of overlay adjustments identified in
accordance with one embodiment of the present invention.
Detailed Description
[0039] A method for automated design for orthotic and prosthetic
devices has been developed that has a high degree of accuracy in
modeling the patients' limb. FIG. 3 shows a schematic of one
embodiment of the present invention with the equipment for an
automated design system 30 for a prosthetic device. In this
embodiment, the patient's limb 32 rests on a positioning
transmitter 34 that is supported by a stand 36. A laser scanner 38
scans the surface of limb and records its dimensions. The patient
wears a sock over the limb 32 that reflects the light from laser.
In some embodiments, the patient may wear multiple socks or a
single sock with multiple layers. The sock is typically made of
white cotton that is capable of reflecting laser light. The
positioning transmitter 34 generates a relative position of the
limb 32 to the scanner 38 through an attached cable 40. The scanner
38 then collects the dimensions of the limb 32 and transmits them
via cable 40 to a computer 42.
[0040] At the computer, the dimensions of the limb are analyzed
with custom software that generates a three dimensional
representation of the patient's limb. FIGS. 4a, 4b, and 4c show
examples of three separate views of the limb generated by the
computer. FIG. 4a shows an outline of a frontal view of the limb
44. FIG. 4b shows a three dimensional frontal view of the limb 46.
Finally, FIG. 4c shows an overhead cross-sectional view of the limb
48.
[0041] Before the computer representations of the limb 44, 46, and
48 can be used to manufacture a prosthetic device, modifications
need to be made to ensure a proper fit. These modifications
necessary to compensate for the presence of the liner as well as
any redundant tissue on the residual end of the patient's limb. As
a patient wears a liner throughout the day, the size of the limb
changes due to the activity of the patient. This variation in limb
size can result in the fit of the prosthetic device becoming loose
and uncomfortable for the patient. In order to compensate for the
change in size, the computer representations of the limb should be
adjusted by the computer.
[0042] First, the overall volume of the limb should be reduced in
volume by up to 12 percent. In some alternative embodiments, the
volume is reduced by about 3 to 5 percent. FIGS. 5a, 5b, and 5c
show examples of three separate views that are generated by the
computer of the limb after the volume reduction. Each view
corresponds with the similar view shown in FIGS. 4a, 4b, and 4c
before the volume reduction. Specifically, FIG. 5a shows an outline
of the frontal view 50 of the limb after a volume reduction 56.
FIG. 5b shows a three dimensional frontal view 52 of the limb after
a volume reduction 56. FIG. 5c shows an overhead cross-sectional
view 54 of the limb after a volume reduction 56. While the
reduction of volume is normally as much as 12 percent of the total
limb volume, it should be noted that amount of the reduction may
vary somewhat outside this range in alternative embodiments.
[0043] Next, the distal length of the model should be reduced.
FIGS. 6a, 6b, and 6c show examples of three separate views that are
generated by the computer of the limb after the distal length
reduction. Each view corresponds with the similar view shown in
FIGS. 4a, 4b, and 4c before the distal length reduction.
Specifically, FIG. 6a shows an outline of the frontal view 60 of
the limb after a distal length reduction 66. FIG. 6b shows a three
dimensional frontal view 62 of the limb after a distal length
reduction 66. FIG. 6c shows an overhead cross-sectional view 64 of
the limb after a distal length reduction 66. The distal length
reduction is a calculated percentage of the thickness of the liner.
Many different types of liners are commercially available.
Consequently, the typical distal end thickness of a liner may range
from 4 mm-16 mm. The percentage of reductions are calculated based
on the characteristics of the individual liners. Such factors in
the calculations include: thickness; type of material; softness
levels; compressibility; rebound rate; elasticity; reaction to
temperature, etc. These factors are usually provided by the liner
manufacturers. As a result, the factors used for different liners
may vary widely in their use and relative weight in
calculations.
[0044] A typical calculation would result in a distal length
reduction of about 2 mm-8 mm of the computer representation of the
limb. However, other liners could have a thickness outside the
normal range of thickness and the distal reduction would vary
accordingly. While the reduction of the distal length is normally
about 2 mm-8 mm or some other calculated percentage of the
thickness of the liner, it should be noted that the amount of the
reduction may be somewhat greater or less in alternative
embodiments.
[0045] Finally, boney prominences of the limb are mapped. These may
include areas, such as the patella (or "knee-cap"), where the
underlying bone is close to the skin of the patient. FIGS. 7a, 7b,
and 7c show examples of three separate views that are generated by
the computer of the limb after the boney landmark mapping. Each
view corresponds with the similar view shown in FIGS. 4a, 4b, and
4c. Specifically, FIG. 7b shows a three dimensional frontal view 72
of the limb after the boney prominences 76 are landmarked. The
prominences 76 are not shown in FIGS. 7a and 7c.
[0046] After the landmarking, the computer software automatically
identifies the areas of the limb that need an overlay. Typically,
areas that need an overlay are areas with landmarks clustered
relatively close together. FIGS. 8a, 8b, and 8c show examples of
three separate views of the limb after the overlay regions are
identified by the computer. Each view corresponds with the similar
view shown in FIGS. 4a, 4b, and 4c. Specifically, FIG. 8a shows an
outline of the frontal view 80 of the limb after the overlay
regions 86 are marked. FIG. 8b shows a three dimensional frontal
view 82 of the limb after the overlay regions 86 are marked. FIG.
8c shows an overhead cross-sectional view 84 of the limb after the
overlay regions are marked 86.
[0047] Once the computer modifications are made to the
representations of the limb, the data is transmitted to a
manufacturing facility. The customized prosthetic socket is then
constructed based on this information. The prosthetic limb is
constructed with minimal inconvenience to the patient since the
measurements of the limb are taken quickly and accurately. The
modifications to the measurements of the limb result in a
comfortable, better fitting prosthetic limb for the patient. The
need for re-measurement or adjustment of the socket is minimal with
the present invention.
[0048] It should be noted that in alternative embodiments, the
modifications to the representations of the limb can be done in any
order. It also should be noted that in alternative embodiments, the
identification of boney prominences may be skipped. While the
embodiments shown have dealt only with a leg amputation below the
knee, it should be noted that the present invention could be
applied in other situations such as a prosthetic arm or an above
the knee amputation.
[0049] FIG. 9 shows a schematic of one embodiment of the present
invention with the equipment for an automated design system 90 for
an orthotic device. In this embodiment, the patient places his foot
92 on a foot block 96. The patient wears at least one or more socks
94 over his foot. The sock 94 is typically made of white cotton
that is capable of reflecting laser light. The patient places his
foot over a concave portion 98 of the foot block 96. The concave
portion 98 allows scanning of the arch of the foot 92. A laser
scanner 100 is used to scan the dimensions of the patient's foot 92
into a computer 104 via a cable connection 102 in a similar manner
as described in FIG. 3.
[0050] At the computer, the dimensions of the foot are analyzed
with custom software that generates a three dimensional
representation of the patient's foot. FIGS. 10a, 10b, and 10c show
examples of three separate views of the foot generated by the
computer. FIG. 10a shows an outline of a side view of the foot 106.
FIG. 4b shows a three dimensional side view of the foot 108.
Finally, FIG. 4c shows an overhead cross-sectional view of the foot
110.
[0051] Before the computer representations of the foot 106, 108,
and 110 can be used to manufacture an orthosis, modifications need
to be made to ensure a proper fit. Specifically, boney prominences
111 of the foot are mapped for boney landmarks as shown in FIG.
10b. These may include areas such as the ankle, where the
underlying bone is close to the skin of the patient. These areas
are mapped in order to provide additional overlays of material.
This provides greater comfort to the patient by providing extra
thickness of material over the boney landmarks. The mapping is done
in a similar manner as previously described for FIGS. 7a-7c and
FIGS. 8a-8c.
[0052] After the landmarking, the computer software automatically
identifies the areas of the foot that need an overlay. FIGS. 11a,
11b, and 11c show examples of three separate views of the foot
after the overlay regions 118 are identified by the computer. Each
view corresponds with the similar view shown in FIGS. 10a, 10b, and
10c. Specifically, FIG. 11a shows an outline of the side view 112
of the foot after the overlay regions 118 are marked. FIG. 11b
shows a three dimensional side view 114 of the foot after the
overlay regions 118 are marked. FIG. 11c shows an overhead
cross-sectional view 116 of the foot after the overlay regions are
marked 118.
[0053] Once the computer modifications are made to the
representations of the foot, the data is transmitted to a
manufacturing facility. The customized orthosis is then constructed
based on this information. The orthosis is constructed with minimal
inconvenience to the patient since the measurements of the foot are
taken quickly and accurately. The modifications to the measurements
of the foot result in a comfortable, better fitting orthosis for
the patient. The need for re-measurement or adjustment of the
orthotic frame is minimal with the present invention.
[0054] In alternative embodiments, the method of scanning the limb
described previously can be used to provide a model for a custom
liner for the patient's limb. The limb is scanned in the same
manner as previously described and shown in FIG. 3. After scanning,
the computer representations of the limb are transmitted to a liner
manufacturing facility. Typically, modifications to the computer
representations are not necessary when creating a customized liner.
However, in alternative embodiments, modifications to the
dimensions of the liner could be made in order to ensure an
optimized fit. A customized liner is then manufactured to
correspond to the specific dimensions of the patient's limb. This
results in a better fitting, more comfortable liner.
[0055] While the embodiments shown have dealt only with an orthosis
for a foot, it should be noted that the present invention could be
applied in other situations such as an orthotic devices for the
knees, arms, the face, or the head. It should be clear that any
part of the body can be scanned and modified in the methods
described here. Alternative embodiments can be used to construct
burn garments and other therapeutic or protective devices.
[0056] While the invention has been described with respect to a
limited number of embodiments, those skilled in the art, having
benefit of this disclosure, will appreciate that other embodiments
can be devised which do not depart from the scope of the invention
as disclosed here. Accordingly, the scope of the invention should
be limited only by the attached claims.
* * * * *